Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/128079
"Frankie" Cathcart had the opportunity to put the GSX-R750 through Its paces at Zolder in Belgium. ing rod s, and a ca re fu ll y w orked -on cylinder head w ith ultrahard berylliumcopper valv e sea ts and relati vely conservative 13:1 compression. It' s all a testament to Su zuki' s d edicated in-hou se d evel opment, ai med initially a t World Superbike success, but a lso ben efiting their road customers . It's no coincidence that the GSX-R750 is th e undisputed champion of the 750cc Supersport class. The result is an engine delivering "over 175 hp" at 14,000 rpm, compared to the 158 hp of last ye a r' s ca rb u rted bike - giving Chili a gre at tool to challe n ge for victory from Laguna Seca onward - th e first time a ll these trick engine components came together. But this vas tly im proved engine performa nce only cou n ts wh en you ge t it to the ground, an d the first part of the season saw Chili struggling to ge t the Suzuki set up to his taste, as well as to persua de Dunlop to make the kind of tires he needed . "The p roblem 1 had at the star t of the yea r was not so m uc h ridi ng a fo u r- . cylinder Superb ike for the first time, bu t changing to new tires and finding the right way to adapt the bike to my ridi ng sty le," says Chil i. "Dunlops requ ire a quite different technique com pa red to the tires I've been using since I cam e to Superbike (Mtche lins) . an d I had to learn how to cha nge my s tyle to suit this , while Dunlop had to develop tires better suited to m y need s. Bu t, in the end , we go t there, and now at the end of the season we ha ve a bike that we've proved is ready to wi n, wet o r dry which is w hy we shall retain it fo r ",.-.---",-A good balan ce by cha nging the offse ts, then a lso adjusting rid e h eigh ts . Th e arriva l of th e new Dunlop front , 'a nd then a new rear compound from Misan o onwards , which works goo d on a ll circu its, a nd lasts a race yery well - excep t a t Brand s Hat ch , but we were n ' t th e only ones in trouble there - tha t was the final ing redi ent I need ed to try for victorv, And eventually , we succeeded." , It takes awhile to accept' how har d yo u reall y can push th e Su zuki in th e turn, but when yo u d o the resul t is a dramatic reduction in lap t im es . O f course, th is means using a lot of lean angle in the corner. But the in-line four cylinder architecture o f th e bike is • tho ught ou t well enough so that nothing drag s . Th is, com b ined with th e rear Du nlop 's goo d side-g rip, plus the con tro llable res ponse of the Nippondenso EFI whe n you get ha rd on the gas to drive ou t of the turn, resu lts in a package tha t d eli vers gift-wrapped con fidence to the rider. "It's tru e that I use a lot more corner speed than before, with th e Ducat i," admi ts Chili, "a nd th at al so means 1 m ust use more angle - but I have to go fast like t h is, till they improv e the engine. Seriously, thou gh , in 1999 Suzu ki worked very hard , a n d so did the team - every race there wa s a small improvement, especially in lo w-speed pickup out of turns, a nd also at high rpm. So now the bike's not so bad - all I think I need is a little bit more accele ration, which would have the extra benefit of giving 3-4 kph (1.8-2.4 mph) more to p -en d s peed , as well as bet ter midrange d rive out of turns. But really, 3 The fuel-Injected GSX-R produced more power than the 1998 carbureted version of the bike. According to the Aistare eam, power was up 17 hp on the new bike - thanks mainly to the Nippondenso electronic fuel-injection system. n next season, rath er than switch just ye t to th e ne w GSX -R750 Suzuk i have announced for 2000." The fac t tha t the multi-adjustable GSX-R750 chassis geo me try is based on Suzuki's wo rks RGV500 GP-winner certainly helped in setup. Once again, the American round of the series was when i\ a ll ca me together for the first time, when Chili led a Worl d Superbike race for the first time on a handling circuit. The Suzuki still doesn 't steer quite as nimbly into a tum as Yamaha's new R7, and it'doesn't flick from sid e to side in a ch ica ne in s u ch a n ag il e w a y a s t h e r;:awasaki ZX-7R - but yo u can keep up corn er speed bet ter on the GSX-R than on ei therof the se bikes, helped by th e .'!utstand ing grip from the Dunlop fro nt tire . Th is is a 16.5-in cher, like the rear, (n t r od u ce d from the N u rb urgring onwa rd to im prove turni ng effect, says Dunl op , but wit h th e sp in -off ben e fit that it' s better ma tched to the rear than tj e 17-incher it replaced , a llow ing teams \D set the bike up bett er . This was one of Chi li's key objectives . " I like a ba la nced bike, with good grip a t bo th ends," he sa ys. "To start wi th, the bike was too heavy at th e fro nt, w ith too high a rear setting. We m a ke many experiments, and find a compared to the sta rt of the season, this is a mu ch bette r packa ge. I neve r tested the carburetor bik e, bu t to begin with the fu el injection had a very fierce pickup from a closed thro ttl e, wh ich, for example, was th e rea son 1 crashed at Doning to n in the ha irp in during the race . The telemetry tells us I opened the throttle only 5 percent - but the power came in strong eno ugh to unhook the back wheel on a dry track. Now we still have a little problem with this , but only in very low gears, first or second, wh en I like to open the thr ottl e wide from 7500 rpm and drive hard ou t of a slow cor ner. But otherwise, it's much better now , and the hand ling is mo re predictable as a result." That a pp lies also und er heavy brakin g, as you must do four times a lap at Zolder. Two years ago, t his would hav e been a recipe for concern on the o ld bike, which didn 't s to p too w ell and wa s very unstable under heavy brak ing, making it hard to pick a line. The '99 GSX-R seems to be far better on th e brakes, with the latest-spec Brern - . bos givi ng lo ts of bite, a ided by the effective engi ne-braking delivered by the slipper clu tch . However, it wasn't always tha t way. Appa re nt ly the bike d id move arou nd a lot under reverse loads a nd heavy bra king , un til so me typical lat er al thinki ng by Alsta re saw the m fi rstly se t th e en g ine-id le very high' (as m uch as 3500-4000 rpm on the bike I was rid ing), then use a couple of so leno ids to inject ai r int o t he cy l in de rs c ha ngi ng fro m thi rd to second a nd second to bo tto m gea rs , to co un terac t th e e ff e ct of th e r e v ers e to r q ue load s . Now, th e slipper clutc h rea lly d oes wo rk properly, and yo u can b rak e ve ry ha rd a nd lat e fro m high speed for any slow turn , without the bike m o v i n g a ro u n d and s n a k in g about as you do so . The Suzuki stays planted - the back end d oesn't chatter under engine in erti a or m o ve about u nd er weight transfer. It's very stable, just as it is in faster turns hard on the power - thou gh here it 's important to use on e g ea r low er ' a n d ke e p th e e n g in e pulling hard at high rpm, to preven t the fro nt from washing out by driving hard through the turn on the gas. And the Showa suspension d oes a good job of putting tha t power to the g rou nd - though it's take n a lot of testing. The team has u sed as many as eight d ifferent rear links and constant experimenta tion of t h e ecce ntric adjust me n t on th e swinga rm pivot to find a se tu p w ith which Chili can go fast. And don' t forge t the three different swingarms, all of varying stiffness . Suzuki has braced up the stock GSXR750 twin-spar alloy chassis with a stru t above the cylinder head to tie the two spars toge ther, and the result is a stifffeeling frame that doesn't twist or move a rou nd when you get hard on the gas co; ~ E G> > o z 23